| Title | Numerical Investigation of Thermo-Hydro-Chemical Processes in Deep Fractured Upper Rhine Graben Formations for Uncertainty-Driven Reservoir Management |
|---|---|
| Authors | Mohamed Abdelmoula |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | #ReactiveTransport #UncertaintyQuantification #Dissolution&Precipitation |
| Abstract | Thermo-hydro-chemical (THC) reactive transport plays a key role in both heat recovery efficiency and sustainable management in deep, high-temperature fractured geothermal reservoirs. Large differences in temperature between the injected brine and the initial reservoir temperature can alter the chemical equilibria, triggering the dissolution and precipitation of minerals that modify the porosity and permeability of the reservoir and fractures. This work presents an integrated workflow that links PHREEQC geochemical simulations with COMSOL Multiphysics calculations via the iCP software. This framework is applied to the Middle Buntsandstein and Muschelkalk formations at the Wörth am Rhein site in the Upper Rhine Graben, where the DEKAPALATIN geothermal project will be implemented. A set of numerical scenarios evaluates how variations in brine composition and mineralogical assemblages influence reservoir behavior. In these scenarios, spatial and temporal variations in reservoir characteristics are investigated. Specifically, detailed alterations in porosity and permeability caused by mineral dissolution and precipitation are assessed, along with their implications for geothermal flow-path development and thermal breakthrough dynamics within the fracture network. The results indicate that secondary precipitation processes, particularly of carbonate minerals, are expected to play an important role in porosity and permeability. In contrast, dissolution processes may encourage the development of additional flow paths or enhance the existing ones. This study advances our understanding of thermo-hydro-chemical interactions in fractured geothermal reservoirs and provides a comprehensive framework for quantifying uncertainty in geothermal reservoir management. The integrated approach enhances the reservoir performance forecasts and supports sustainable decision-making for low-risk geothermal exploitation. |